Device for applying a layer of adhesive on an endless belt in a screen printing machine

ABSTRACT

In screen printing machines, in the vicinity to the belt adapted to carry the strip material to be printed, there are provided belt adjustable guiding means for deforming the belt so that its cross-section exhibits a configuration having a central portion of variable width, slightly protruding relative to the two remaining marginal portions, whereby the coating roll bears only against said belt central portion.

United States Patent [1 1 [111 3,809,009 Gerard 1 May 7, 1974 [54]DEVICE FOR APPLYING A LAYER OF 2,054,822 9/1936 Keith 12/80 A H ON AENDLESS BELT [N A 807,685 l2/l905 Pelham 118/257 X 3,627,557 12/1971Sato et a1 117/37 LE SCREEN PRINTING MACHINE 2,606,520 8/1952 Hoel118/249 [75] Inventor: Stierlein Gerard, 1,399,975 12/1921 McConnell118/257 Mulhouse-Bourtzwiner France Kaneko 6t 31 3,310,304 3/1967 Foiaset a1. 101/232 X [73] Assignee: Societe Alsacienne de Constructions 255,3 10/1953 Geiringer Mecaniques de Mulhouse, 2,406,056 8/1946 Barrett118/262 Mulhouse, France [22] Filed: 1972 Primary Examiner-Morris Kaplan[21] Appl. No.: 237,139 Attorney, Agent, or Firm1-lolman & Stern ForeignApplication Priority Data Apr. 1, 1971 France 71.11467 [57] ABSTRACT ClIn screen printing machines, in the vicinity to the belt 6/247 adaptedto carry the strip material to be printed, there [51] Int. Cl. 1. B05611/00 are provided belt adjustable guiding means for de- Field of Search118/44, 0, forming the belt so that its cross-section exhibits a 118/262, 2 111 B, 1 11 configuration having a central portion of variable5 /547, 549 width, slightly protruding relative to the two remainingmarginal portions, whereby the coating roll bears only [5 6] ReferencesCited against said belt central portion.

UNITED STATES PATENTS 1,618,809 2/1927 Byron et a1. 1 17/44 UX 6 Claims,4 Drawing Figures mminm H974 3809.009

sum 1 [IF 2 DEVICE FOR APPLYING A LAYER OF ADHESIVE ON AN ENDLESS BELTIN A SCREEN PRINTING MACHINE BACKGROUND OF THE INVENTION The inventionrelates to a device for applying a layer of adhesive on an endless beltadapted to support a strip to be printed in a screen printing machine.It relates more particularly to rotary cylindrical screen machines butit is also applicable to frame or flat screen printing machines.

In such machines, the material to be printed, generally a piece offabric, is temporarily fixed on the endless belt which will transportthe material during the printing operation, by applying on said belt,upwardly of the screen area, a layer of a suitable adhesive through aset of rolls successively engaging with each other and the first ofwhich rolls, or the supplying roll, is immersed in a tank filled withadhesive, while the last roll, or coating roll, is in contact with thebelt. The adhesiveness of the adhesive substance utilized issufficiently weak for the fabric to be easily stripped off the beltunder the mere effect of the tension imparted thereto by taking-up meansat the delivery end of the machine.

PRIOR ART It is useless and even harmful for the belt to be covered withadhesive over the whole width thereof, particularly in cases in which afabric of a width substantially smaller than the width of the belt is tobe printed. This is why the machines of this type are generally providedwith a device enabling adjustment of the width over which the belt iscovered with an adhesive. However, the known devices utilize means whichdirectly act upon the width of the rolls which apply the adhesive on thebelt, and/or upon the width of the rolls which are immersed in theadhesive tank, often provided themselves with displaceable sidepartitions; such devices are relatively complicated, their tightness isnot always satisfactory and their operation is rather difficult.

OBJECT AND SUMMARY OF THE INVENTION Therefore, an object of theinvention is to provide a width adjustable adhesive laying device forbelts of printing machines, which obviates the abovementioned defects ofthe known devices.

For this purpose, according to the present invention, adjacent thecoating roll, there are provided adjustable belt guiding means capableof deforming said belt so that the belt can assume a configuration whosecrosssection has a central portion of variable width which slightlyprotrudes on the outer face relative to the two remaining marginalportions thereof, whereby the coating roll engages only the centralportion of said belt.

Due to this particular structure, all of the parts of the adhesivelaying system including the tank, the supplying roll, the coating rolland the intermediary laminating roll or rolls are of unvariablecharacteristics, irrespective of the width to which the band must becovered with adhesive. Only the belt portion to be coated with adhesive,i.e., the portion which slightly protrudes with respect to the marginalportions thereof, may be reached by the coating roll, so that the twoportions of said roll which are situated beyond the width of the belt tobe treated although also coated with adhesive, remain inoperative andcannot apply adhesive onto the belt since they are not in contact withthe marginal portions thereof.

According to a preferred embodiment of the invention, the coating rollis carried by a shaft which also carries two supporting rollers, havinga diameter slightly larger than that of said coating roll, at both endsthereof, for supporting said marginal portions of the belt. Said twosupporting rollers act to prevent the marginal portions of the beltlifted by said adjustable guiding means, from lowering and producingdeformations which could entail irregularities across the width of thecoated portion of the belt.

In one particular embodiment, said adjustable guiding means comprise tworotary adjusting rollers which support, respectively, the two marginalportions of the outer surface of the lower run of the endless belt, withsaid two rollers being idly mounted on two aligned shafts, whileadjusting control means permit the vary ing of the spacing of said tworollers.

The invention will be more clearly understood from the followingdescription with reference to the accompanying drawings, whichrepresent, by way of example only, one embodiment of an adhesive layingdevice for the endless belt of a rotary screen printing machineaccording to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings FIG. 1 is adiagrammatic side view of the device, in an operative condition,

FIG. 2 is a cross section taken on line II-II of FIG. 1, the viewlooking in the direction of the arrows,

FIG. 3 is a cross section, taken on line IlIIII of FIG. 1, and

FIG. 4 is a view similar to FIG. 1, but showing the device at rest, ininoperative position.

DETAILED DESCRIPTION OF THE INVENTION The device shown in FIG. 1 isintended to apply a layer of adhesive on an endless belt 1 ofa rotaryscreen printing machine, with said adhesive laying being effectivelymade only on a central portion of width L (see also FIG. 3) of the belt.

An adhesive 3 contained in a tank 4 is transferred to the belt 1 by aset of rolls, three in the present embodiment, which comprises a firstroll or supplying roll 5, immersed in the adhesive contained in thetank, an intermediary roll or laminating roll 6 in contact with thesupplying roll 5 and a coating roll 7 which, when the device is anoperative position as shown in FIG. 1, is simultaneously in contact withthe laminating roll 6 and with the lower face or outer face of the lowerrun of the endless belt 1, in proximity to an end drum 8 around whichthe belt flexes.

The assembly consisting of the tank 4, the supplying roll 5 and thelaminating roll 6 is carried by a support 11 which may slidehorizontally on slide-bars 12, in such a way that the laminating roll 6may move towards or away from the coating roll 7, as can be seen bycomparing FIGS. 1 and 4. Bearings 14 of the supplying roll 5 andbearings 15 of the laminating roll 6 are slidingly mounted in inclinedslide-bars 16, the direction of which is substantially radial relativeto the coating roll 7. The bearings 14 are connected respectively topiston rods 18 of two pressure fluid rams 19, cylinders 22 of which aresecured the support 11 on each side of the machine. Rams l9 permit thesupplying roll 5 to be applied against the laminating roll 6 and,therefore, the latter to be applied against the coating roll 7 with asuitable pressure according to the quantity of adhesive which it isdesired to apply to the printing belt 1.

The ends of a shaft 25 of the coating roll 7 are journaled in the endsof two arms 26, the other ends of which are fixedly secured to twoshafts 28 rotatably mounted in brackets 29 secured to a frame 9 of themachine, on each side thereof. By pivoting the arms 26, the coating roll7 may be brought against the belt 1, as shown in FIG. 1, or, on thecontrary, said coating roll 7 may be moved away therefrom, as shown inFIG. 4. This displacement is achieved, in the present embodiment, bymeans of two further pressure fluid rams 32, cylinders 33 of which arepivoted, through pins 34 on brackets 35 secured to the frame 9 of themachine, while rods 37 of the pistons of said rams are pivotally mountedat their ends, on ends 38 of levers 39 which are extensions of arms 26.

The adhesive laying width on the belt may be adjusted as desired bymeans of belt adjustable guiding means which, in the present embodiment,are in the form of two rotating rollers 44, 44A of variable spacing.Each of said rollers, e.g., roller 44, is idly rotatably mounted, forexample, through two ball bearings or the like 45, 46, on a nut member47 engaged on a horizontal screw threaded bar 48 which is journaled atits two ends in two bearings 51, 52 secured to a cross-beam 54 of themachine frame 9. The nut member 47 is provided with a depending flange55, the edge of which has a rectilinear portion in sliding engagementwith the cross-beam 54, so that said nut member may slide on saidcrossbeam without rotating on itself. The screw threaded bar 48 may berotated, for example, by means of a manual adjusting control wheel 57secured to one end of said bar.

Roller 44A is mounted in the same manner as roller 44 and thecorresponding parts have been designated by the same reference numeralsbearing the suffix A. Thus, by rotating the two screw threaded bars 48,48A in a given direction or in the reverse direction, through manualcontrol wheels 57, 57A, the two rollers 44, 44A may be displaced asdesired towards or away from each other, according to the width L of theportion of the belt which is tobe coated with adhesive. Moreover, theindividual positioning adjustment of the two rollers permits, ifnecessary, to lay adhesive on a portion of the endless belt which is notnecessarily centered with respect to the over-all width of said belt.

The diameter and the vertical positioning of the two rollers 44, 44A aresuch that said rollers slightly lift the corresponding marginal portionsof the belt 1 above the level normally reached by the lower run of saidbelt in proximity to the driving drum 8 thereof. Moreover, slightlyupwardly of the two adjusting rollers 44, 44A, there is provided aguiding roll 61 of even diameter throughout its length and against whichbears the upper or inner face of the lower run of the belt I. Saidguiding roll is provided for enabling the rollers 44, 44A to achieve,with a better accuracy, the particular configuration of the beltcross-section shown in FlG. 2, since the central portion of the belt tobe coated is maintained by said roll, and by the driving drum 8respectively, immediately upwardly and downwardly of the area of the twoadjusting rollers 44,44A and the coating roll 7.

The shaft 25 of the coating roll 7 carries at both ends thereof twosupporting rollers 63, 63A (FIG. 3), the diameter of which is slightlylarger than that of said coating roll, so that when the deformed centralportion of the belt bears upon the coating roll 7, the slightly liftedmarginal portions of said belt naturally bear upon said two supportingrollers 63, 63A thus, the latter contribute to accurately maintain theconfiguration of the cross-section of the belt imparted thereto by thetwo adjusting rollers 44, 44A.

The coating roll 7 is rotatably driven by shaft 10 of the belt drivingdrum 8 through a gear drive which comprises a toothed wheel 71 securedto the shaft 10, a chain 72 which passes around said wheel and aroundanother toothed wheel 73 idly mounted on one of shafts 28, a gear 74fixedly secured to the toothed wheel 73 and a gear 75 in mesh with gear74 and fixedly secured to shaft 25 of the coating roll 7 (FIGS. 1 and3).

When the machine is stopped, and the adhesive laying device is in aninoperative position, the coating roll 7 occupies its lowermost position(FIG. 4) in which it is spaced from the belt and the support 1 1 issufficiently remote for the laminating roll 6 not to be in contact withsaid coating roll 7.

Prior to starting the adhesive laying device, the spacing of the tworollers 44, 44A is adjusted according to the width L of the belt whichis to be coated. The coating roll 7 is lifted against the belt by therams 32, as shown in FIG. 1, and the sliding support 11 is advanceduntil the laminating roll 6 is in contact with the coating roll 7. Thethickness of the adhesive layer to be applied to the belt 1 is adjustedby varying the pressure of the fluid admitted in the rams 19 which pushthe laminating roll 6 against the coating roll 7. The coating roll 7 isrotatably driven at the same peripheral speed as that of the belt 1 dueto th particular characteristics given for this purpose to the chain andgear transmission (72, 71 73, 74, 75) connecting the shaft of the beltdriving drum 8 to the coating roll shaft 25.

While only one embodiment of the invention has been shown and described,it is to be understood that modifications can be made without departingfrom the scope of the appended claims.

I claim:

1. In and for a web material processing machine having a flexiblesupporting band. with an inner inactive face and an outer face adaptedto receive the web material, a device for laying adhesive on said outerface of the supporting band for retaining the web material, said Idevice comprising a set of rolls successively in contact with eachother, a tank containing an adhesive, a first of said rolls being asupply roll immersed in the adhesive of said tank, a last of said rollsbeing a coating roll in contact with said outer face of the supportingband and a pair of guiding means located in the vicinity of the coatingroll for supporting a portion of the width of the supporting band somedistance away from the surface of the remaining portion of thesupporting band, means adjustably mounting said pair of guiding meansfor movement toward or away from each other for varying the width ofsaid portion of the supporting band, a shaft carrying said coating roll,two supporting rollers carried by said shaft, and said supportingrollers having a diameter slightly larger than the diameter of saidcoating roll for supporting said portion of said supporting band,whereby said coating roll bears only on said remaining portion ofvariable width of said supporting band.

2. In and for a web material processing machine having an endless beltforming upper and lower runs with an innerface and an outer face adaptedto receive the web material, a device for laying adhesive on the outerface of the lower run of the belt for retaining the web material, saiddevice comprising a set of rolls successively in contact with eachother, a tank containing an adhesive, a first of said rolls being asupplying roll immersed in the adhesive of the tank, a last of saidrolls being a coating roll in contact with the outer face of said lowerrun of the endless belt, a pair of guiding means located in the vicinityof the coating roll for supporting the marginal portions of said belt ata level slightly higher than the level of the unsupported centralportion of said belt, means adjustably mounting said guiding means formovement toward and away from each other for varying the width of theunsupported central portion of the belt, a shaft carrying said coatingroll, two supporting rollers carried by said shaft, and said supportingrollers having a diameter slightly larger than the diameter of saidcoating roll for supporting said marginal portions of said belt, wherebysaid coating roll bears only on said belt central portion of variablewidth. x

3. The adhesive laying device according to claim 2, wherein saidadjustable guiding means consists of two adjusting rotative rollerslocated respectively under said marginal portions of the outer face ofthe lower run of said belt, said device further comprising two shaftswhich are aligned transversely of said belt, said rollers being idlymounted on said aligned shafts, and adjusting controlmeans for varyingthe spacing of said rollers.

4. The adhesive/laying device according to claim 3, wherein said shaftwhich carries each adjusting roller consists of a screw threaded bar,said device comprising for each of said screw threaded bars two fixedbearings and an adjusting control member for adjustment by rotation ofsaid bar in said bearings, each of said screw threaded bars carrying anut member, each nut member being provided with means for preventing itsrotation relative to said bearings, and said adjusting rollers beingidly rotatably mounted on said nut members.

5. The adhesive laying device according to claim 2, wherein a guidingroll of even diameter along its whole length is disposed against theinner face of the lower run of said endless belt, in the proximity ofthe belt adjustable guiding means.

6. In and for a screen printing machine having an endless belt with anouter face and an inner face adapted to receive a sheet material to beprinted, and a driving rotary drum around which said endless beltflexes, said belt extending horizontally and having an upper run and alower run; an adhesive laying device according to claim 2, wherein saidcoating roll is connected to said driving drum of said belt through adesmodromic transmission, whereby the peripheral spaced of said coatingroll is equal to the linear speed of said belt.

UNITED STATES PATENT FFICE CERTIFICATE OF CORRECTION Patent No. 3809009Dated May 7, 1974 nv Gerard Stierlein It is certified that error appearsin the aboveidentified patent and that said Letters Patent are herebycorrected as shown below:

[751 Inventors GERARD STIERLEIN Signed and sealed this 17th day ofDecember 1974.

(QT-TALL) Attest: I v

B- cCOY M. GIBSON, JR. MARSHALL DANN Attesting Officer Commissioner ofPatents POIO50 (10-69) USCOMM-DC 60376-P69 US GOVERNMENT PRINTING OFFlCE"I9 0-I!6i-3ll.

1. In and for a web material processing machine having a flexiblesupporting band with an inner inactive face and an outer face adapted toreceive the web material, a device for laying adhesive on said outerface of the supporting band for retaining the web material, said devicecomprising a set of rolls successively in contact with each other, atank containing an adhesive, a first of said rolls being a supply rollimmersed in the adhesive of said tank, a last of said rolls being acoating roll in contact with said outer face of the supporting band anda pair of guiding means located in the vicinity of the coating roll forsupporting a portion of the width of the supporting band some distanceaway from the surface of the remaining portion of the supporting band,means adjustably mounting said pair of guiding means for movement towardor away from each other for varying the width of said portion of thesupporting band, a shaft carrying said coating roll, two supportingrollers carried by said shaft, and said supporting rollers having adiameter slightly larger than the diameter of said coating roll forsupporting said portion of said supporting band, whereby said coatingroll bears only on said remaining portion of variable width of saidsupporting band.
 2. In and for a web material processing machine havingan endless belt forming upper and lower runs with an innerface and anouter face adapted to receive the web material, a device for layingadhesive on the outer face of the lower run of the belt for retainingthe web material, said device comprising a set of rolls successively incontact with each other, a tank containing an adhesive, a first of saidrolls being a supplying roll immersed in the adhesive of the tank, alast of said rolls being a coating roll in contact with the outer faceof said lower run of the endless belt, a pair of guiding means locatedin the vicinity of the coating roll for supporting the marginal portionsof said belt at a level slightly higher than the level of theunsupported central portion of said belt, means adjustably mounting saidguiding means for movement toward and away from each other for varyingthe width of the unsupported central portion of the belt, a shaftcarrying said coating roll, two supporting rollers carried by saidshaft, and said supporting rollers having a diameter slightly largerthan the diameter of said coating roll for supporting said marginalportions of said belt, whereby said Coating roll bears only on said beltcentral portion of variable width.
 3. The adhesive laying deviceaccording to claim 2, wherein said adjustable guiding means consists oftwo adjusting rotative rollers located respectively under said marginalportions of the outer face of the lower run of said belt, said devicefurther comprising two shafts which are aligned transversely of saidbelt, said rollers being idly mounted on said aligned shafts, andadjusting control means for varying the spacing of said rollers.
 4. Theadhesive/laying device according to claim 3, wherein said shaft whichcarries each adjusting roller consists of a screw threaded bar, saiddevice comprising for each of said screw threaded bars two fixedbearings and an adjusting control member for adjustment by rotation ofsaid bar in said bearings, each of said screw threaded bars carrying anut member, each nut member being provided with means for preventing itsrotation relative to said bearings, and said adjusting rollers beingidly rotatably mounted on said nut members.
 5. The adhesive layingdevice according to claim 2, wherein a guiding roll of even diameteralong its whole length is disposed against the inner face of the lowerrun of said endless belt, in the proximity of the belt adjustableguiding means.
 6. In and for a screen printing machine having an endlessbelt with an outer face and an inner face adapted to receive a sheetmaterial to be printed, and a driving rotary drum around which saidendless belt flexes, said belt extending horizontally and having anupper run and a lower run; an adhesive laying device according to claim2, wherein said coating roll is connected to said driving drum of saidbelt through a desmodromic transmission, whereby the peripheral spacedof said coating roll is equal to the linear speed of said belt.